1. Field of the Invention
The present invention relates to an ink jet recording apparatus for executing recording by ejecting ink onto a recording medium, and more particularly, to an arrangement of a recovery unit for protecting a recording means such as a recording head, and the like.
2. Related Background Art
Inkjet recording apparatuses eject ink onto a recording medium from nozzles disposed on a recording head. The tips of the nozzles are disposed on a flat surface called a nozzle surface. The nozzle surface of the recording head is covered by a cap of a recovery unit, whereby it is protected as well as prevented from being dried. The cap includes a suction port which is formed on the bottom thereof and communicates with a suction means such as a pump means and the like. By suctioning ink from the recording head the suction means prevents clogging due to dusts deposited on the nozzles and ink adhered thereto, and further overcomes a disadvantage and the like caused by bubbles. An absorbing member composed of a porous material is disposed in the cap, and when a pump suctions ink, the absorbing member suctions the ink deposited on the nozzle surface and prevents the ink from remaining on the nozzle surface. Without the absorbing member, when the cap is separated from the recording head after the ink has been suctioned, a large amount of ink remains on the nozzle surface and in the cap and is liable to scatter around the nozzle surface.
Further, when time elapses in a state in which a large amount of ink is deposited on the nozzle surface, there is a possibility that the ink in the vicinity of the nozzles enters the recording head through the nozzles, from which a problem of color mixture arises in ink jet recording apparatuses using a plurality of colors. As a result, colors are set erroneously, and it is difficult to execute proper recording.
To remove the remaining ink, it is also possible to wipe it. When, however, a large amount of ink remains, a large amount of ink is also removed by the wiping operation, which requires an additional means for holding the removed ink. Further, when the large amount of ink remains, there is a possibility that the ink scatters by the wiping operation. Therefore, the absorbing member in the cap is an effective means for minimizing the remaining ink.
A suction operation called idle suction may be executed to discharge the ink in the cap by the pump means. In this case, a relationship between the absorbing member and the suction port is important. That is, when the absorbing member securely comes into intimate contact with the suction port, the ink held by the absorbing member is discharged. However, when there is a gap between the absorbing member and the suction port, almost no suction force acts on the absorbing member, thereby so-called defective idle suction is executed.
When the defective idle suction is executed, since the ink remains held by the absorbing member, the absorbing member cannot exhibit a suction capability more effectively. Thus, the ink being held is stored in the vicinity of the nozzles, thereby there is a possibility that the problem of the ink mixture becomes more serious.